The present invention relates in general to semiconductor devices and their fabrication. More specifically, the present invention relates to improved fabrication methodologies and resulting structures for a photodetector having a junction region doping profile that can be tuned to provide a higher doping concentration adjacent the photodetector contact surface, thereby improving contact resistance.
All objects emit some form of thermal radiation, usually in the infrared (IR) spectrum. IR radiation is invisible to the human eye but can be detected by an IR photodetector (or sensor) that is configured to accept and interpret IR radiation. In a typical IR photodetector, the photodetector absorbs radiation and performs a transducer operation that converts the radiation to a measurable electronic parameter (e.g., voltage, current, resistance, etc.). One type of photodetector uses a solid-state or semiconductor p-n junction. The band gap energy of the semiconductor determines the wavelength(s) of the radiation it can absorb. The p-n junction performs the transducer operation that coverts the radiation absorbed by the semiconductor material into a measurable electronic parameter. Photodetectors are used in many applications. For example, televisions use an IR photodetector to detect and interpret the IR radiation sent from a remote control. The benefits of IR photodetectors include low power requirements, simple circuitry and portable features.